The invention relates to a portable type current transformer calibrating device which comprises a voltage regulator T, a no-load current transformer T1, an auxiliary current transformer T2 for artificial load, a current raiser T3, a transformer T4, an artificial load voltage transformer T5, a negative artificial load voltage transformer T6, a 1A/5A standard current transformer T7, a resistor R, an impedance Z, connecting terminals LA, LB, K1 and K2, a relay and a microcomputer type transformer checking meter HEW. In the calibrating device, a traditional method can be used to calibrate a 15-600/5,1A current transformer; and an indirect method can also be used by adopting a current transformer method and the measurement of a primary exciting current, i.e. error and ratio error compensation values are measured under 5 percent of rated current according to the traditional method so as to guarantee the measuring accuracy, then the measurement of the primary exciting current is adopted to calculate, and errors are displayed. In the process of measuring, a primary current connecting lead does not need to be disconnected, and the measurement can be finished in one step. The measurement is accurate, and both actual wire connecting and testing are also convenient.